BACKGROUND ART
Fluid level controllers are used in a wide variety of applications to monitor the level of fluids in reservoirs or containers to ensure that a desired fluid level is maintained. Most often, such fluid level controllers are of an electrical type which senses the level of fluid in the reservoir being monitored and determines, electronically, when and how much fluid to add from a supply source to maintain the level of fluid in the reservoir at a desired level. However, such electronic controllers suffer from several drawbacks. For one, such controllers require an external power source to power the electronic components. This limitation makes an electronic controller susceptible to malfunctioning caused by a power outage. When the fluid reservoir being monitored is needed for a manufacturing operation, even temporary malfunctioning of the electronic controller can seriously disrupt a manufacturing process. If the reservoir being monitored is used in a chemical manufacturing process, a fluid shortage can affect the desired composition of the fluid, thereby detrimentally affecting the manufacturing process itself or components manufactured from the process. Conversely, an overflow of the reservoir is equally problematic since the contents of the primary reservoir often comprise a chemical composition which can represent a serious hazard to the environment should the reservoir overflow. Thus, preventing an overflow of the reservoir is just as important as maintaining a proper fluid level therein and, in some instances, even more important.
Electronic controllers are often relatively complicated devices having a number of independent parts that are susceptible to temperature, humidity and other environmental factors. Failure, or even intermittent malfunctioning, of just a single electronic component can often result in malfunctioning of the entire controller and hence overflow of the primary reservoir.
Still another drawback with conventional electronic controllers is their cost. These devices often represent a significant investment to the user. Installation is also not always straightforward and often requires highly skilled technicians to install and calibrate the controller. Frequently re-calibration of an electronic controller is needed to maintain optimum performance.
Another option for maintaining a fluid level within a reservoir at a desired level is simply periodically manually adding fluid as needed. Obviously, this also has a number of drawbacks, not the least of which is the manpower required to continuously monitor the reservoir and to add fluid as needed. This method is also susceptible to human error and does not lend itself easily to those applications where refilling is needed on a highly frequent basis to maintain the fluid level of a reservoir within a narrow predetermined range.
Accordingly, it is a principal object of the present invention to provide a fluid level controller which can be reliably used to maintain the level of a fluid within a fluid reservoir with no risk of overflow to the reservoir, and without the need for an electrically powered circuit for monitoring and adding fluid to the reservoir as needed.
It is another object of the present invention to provide a fluid level controller which is completely mechanical in its operation, and therefore which is not susceptible to the shortcomings of electronic fluid level controllers.
It is another object of the present invention to provide a fluid level controller which is operable to monitor the level of, and replenish if needed, the fluid within a primary reservoir without the need for complicated electronic fluid level monitoring equipment.
It is another object of the present invention to provide an entirely mechanical fluid level controller which operates to monitor and precisely add fluid, as needed, to a primary reservoir, and which eliminates entirely the chance of an overflow of the primary reservoir because of having added too much fluid to the primary reservoir.
It is still another object of the present invention to provide a fluid level controller that requires virtually no periodic maintenance, can be implemented in a variety of operating environments with little or no modification to a reservoir with which it is used, is cost efficient to construct and operate, and is generally not susceptible to variations in ambient temperature, humidity or other environmental factors which could affect conventional electronic controller systems.